[iOS] Playback stops mid song

- iOS 11.4.1 (and if i remember correctly it also appeared on 11.4)
- Foobar2000 1.1.9 (definitely had this issue on 1.1.8 as well)
- iPhone 8
- I only use mp3 files
- bluetooth connections to headphones and a Raspberry Pi is effected
- wired connections like Apple headphones (Thunderbolt connector), third party headphones (with Thundbolt-Jack-Adapter) and replay in 'dock mode' are effected too

In 9 out of 10 attempts Foobar is not able to play first song without interruption. After replay has stopped suddenly and I want to wake the phones screen, briefly the Foobar app can be seen but it dissappears straight away, like its been terminated.